In-situ synthesis mechanism of nano-layered ternary Ta2AlC

Ta2AlC ceramics were synthesized by self-propagating high-temperature/in-situ reaction method. Effect of preheating temperature and Al content on the phase composition and microstructure of the as-synthesized Ta2AlC was investigated. The phase composition and microstructure of the samples were determined by XRD and SEM, respectively. The synthesis mechanism was concluded by DSC, combining with the reaction products, probable middle-products and system heat absorption. The results indicate that preheating temperature at 250 is propitious to the synthesis of high-purity Ta2AlC. Proper excessive Al can result in the element diffusion for the synthesis of high-purity Ta2AlC. When Ta2AlC is synthesized by SHS, Al melts into liquid first, and then Ta reacts with C to release a large amount of heat and Ta reacts with Al to generate Ta-Al intermetallic triggered by the exothermal reaction between Ta and C. Ta2AlC is mainly synthesized by the reaction of Ta2C and Al together with possible reaction of TaC with Ta-Al intermetallic. ©, 2015, Chinese Ceramic Society. All right reserved.